LeetCode 100. Same Tree

分析

难度         易

来源

https://leetcode.com/problems/same-tree/

题目

Given two binary trees, write a function to check if they are the same or not.

Two binary trees are considered the same if they are structurally identical and the nodes have the same value.

Example 1:

Input:     1           1

               /          /

             2   3     2   3

          [1,2,3],   [1,2,3]

Output: true

Example 2:

Input:     1         1

               /          

             2             2

           [1,2],     [1,null,2]

Output: false

Example 3:

Input:     1         1

               /        /

            2   1     1   2

          [1,2,1],   [1,1,2]

Output: false

解答

参考 https://www.cnblogs.com/grandyang/p/4053384.html

package LeetCode;

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class L100_SameTree {
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if(p==null&&q==null)
            return true;
        if((p==null&&q!=null)||(p!=null&&q==null)||(p.val!=q.val))
            return false;
        return isSameTree(p.left,q.left)&&isSameTree(p.right,q.right);
    }
}